As the critical dimensions for electronic device displays continue to shrink in thickness, while increasing in overall size, there is an increased need for semiconductor process equipment that can adequately support and process large, extremely thin substrates disposed in a process chamber.
Typically, substrates were thick enough to be handled in large sheets and supported by pins or roller systems to be placed in a process chamber for processing (e.g., glass used in Thin Film Transistor Liquid Crystal Displays (TFT-LCDs)). An electrostatic chuck is typically physically located and fixed within a process chamber and generally supports and retains a substrate in a stationary position within the chamber. While the substrate is held by an electrostatic chuck (e-chuck), various processes are applied to the substrate to, for example, deposit or remove material from the surface of the substrate. However, large ultra-thin substrates (e.g., between about 10 to 200 microns thick, and about 500 mm square to about 3 meters square) are more like thin foils, for example, that cannot be handled in sheets the same way standard thickness glass (e.g., about 0.7 mm). Furthermore, current process chambers are not equipped to handle roll-to-roll processing of ultra-thin substrates.
In addition, the inventors have observed that handling large sheets of thin glass, required for next generation displays, is difficult since electrostatic chucks may not dechuck easily due to the dielectric nature of glass surface (i.e., no charge dissipation).
Thus, the inventor has provided methods and apparatus for supporting ultra-thin substrates in existing process chambers.